Fluid pressure actuated well shut-off valve



Jan. 16, 1962 R. H. MAGILL ETAL FLUID PRESSURE ACTUATED WELL SHUT-OFF VALVE 2 Sheets-Sheet 1 Filed July l, 1957 f n fu f E M MH! a y MP i L 5. w ,fw L M a MM 2, d d J d Y 4 a e m f5 J2 d d V J ,J C J :7J vw MM 4 5 2,. @a Q A A, ,I LE L- L A 3 fr f E 7 WL M 4 4 a/ 4 f fw V 7 ,9d/JI JJ 5 f. a M w viii" .In un? Jan. 16, 1962 R. H. MAGILL ETAL FLUID PRESSURE ACTUATED WELL SHUT-OFF VALVE 2 Sheets-Sheet 2 Filed July l, 1957 emesse iaten'ied Jan. 16, 1962 3,016,955 FiUUlll) PRESSURE ACTUATED WELL SHUILUFF VALVE Robert H. Magill and .iohn S. Page, Long Beach, Calif.,

assignors to Page @il Tools, luc., `thong Beach, Calif.,

a corporation of Caiitornia Filed .Euly l, i957, Ser. No. 669,9?2 11 Claims. (Cl. l66-224) The present invention relates to well dow controlling apparatus, and more particularly to novel and improved means for controlling the ilow of production fluid from a well responsive to such iiow.

In the oil and gas weii field, it is often desirable to shut ofi the dow of production fluid from the well under certain conditions, for instance, to enable the performance of various down hole well operations. In addition, it is sometimes necessary to shut E the tiow in the event of certain conditions such as over pressure, under pressure, disruption of the well head equipment or the like.

Conventionally, however, valves for controlling the flow of such wells have been located at the well head, where damage to the well head equipment may cause damage to the tiow controlling valve, or to the conventional blow-out preventer at the well head, or such control devices have `required certain tubing manipulations or other manual control.

jIn copending application, Serial No. 669,043 filed July l, 1957, there are disclosed an improved method of and appanatus for controlling the iiow of production from a well, wherein pressure is imposed upon iiuid in the annulus between the casing and the production tubing to operate a valve assembly located in a tubing string down in the well, and wherein a reduction in such pressure for any reason will serve to permit the valve to be closed automaticaly responsive to the ilow of production fluid.

The present invention more particularly concerns a novel valve for use in the method and apparatus of the aforementioned copending application.

An object of the present invention is to provide a valve assembly adapted to be disposed in -a string of production tubing at a point spaced downwardly from the well head, said valve assembly including fluid pressure operated valve means adapted to be held open responsive to production iiuid pressure, and adapted to be closed at will or automatically upon a drop in pressure in the annulus as the result of an excessive rise or decline in production pressure, or as the result of the casing head being displaced or damaged for any reason to such an extent as to allow leakage.

Oitentimes iiowing wells are left untended for substantial periods of time, especially in the case of offshore wells, and as a consequence should an emergency arise `at the well, such as a break in the casing or casing head, rupture of a iiow line, or the like, shutting cti of the well flow is highly desirable, since otherwise the production will be lost and a tire hazard may be produced.

Countless barrels of oil may be lost, as the fluid -runs oit on the ground or ilows into the water from an otishore well. `ln the case of the latter type of well the well may be inaccessible because of a storm, and indeed, the entire platform, it a platform be employed, may be destroyed or severely damaged and the tubing and casing ruptured under water thus substantially hampering shutting off or controlling the l'low.

A further problem is involved where excessive pres sures are produced Aabove the capacity of the tubing, well head equipment or the like, whereupon the well head equipment may be blown oil or damaged and the well will blow out. In the alternative, ow pressure may be abnormally reduced to a dangerously low point where dow should be temporarily halted. Otherwise the well i may cease production, following which swabbing of the well may be required in order to cause resumption of production. The valve hereof, in accordance with the preceding objective, obviates these problems.

A further object is to provide well flow controlling apparatus, including means for packing ot the annulus between a string of production tubing and well casing below the valve assembly hereof, and means for imposing production uid pressure on fluid filling the annulus above the packer, the valve being so constructed as to be held held open responsive to pressure in the annulus, and being adapted to be closed responsive to production fluid iiow upon reduction of the annulus fluid pressure.

Another object is to provide a valve assembly and valve for installation ina string of production tubing, said valve being so constructed that the valve offers no obstruction to the tiow of duid through the tubing or to the passage therethrough of any type of tool which may be run into the well on a wire line, such as perforating guns, fracturing tools, cementing tools, testers or the like In accordance with the preceding objective, it is a further object to provide a valve assembly including an elongated hollow housing, means defining an actuator cylinder including a sleeve in said housing, said housing having a port for admitting fluid into the actuator cylinder to shift the sleeve axially relative to the housing, a valve seat in said housing, and a valve shiftably disposed in the housing and movable towards said seat by said sleeve.

Still another object is to provide a valve assembly according to the next preceding objective, wherein the assembly includes a pivoted gate type valve, the valve being pivotally mounted for seating engagement in a seat formed in the housing and being adapted to be moved to an open position where it is recessed in the housing so that there is no restriction of the passageway through the valve assembly to prevent the passage therethrough of Well tools on a wire line, the passageway through the valve assembly being at least as large in cross sectional area as the minimum cross-sectional area of the tubing string and couplings.

Yet another object is to provide a valve assembly according to the foregoing objectives, wherein the gate valve is operatively connected to the iiuid pressure operated sleeve, so that movement of said sleeve in. opposite directions will etiect closing and opening of said valve.

Another object is to provide a valve in accordance with the next preceding objective, wherein the sleeve is axially extended for engagement with the valve gate so as to aid in maintaining the gate properly seated irrespective of play in the gate mounting.

Other objects and advantages will be hereinafter described as will become apparent to those skilled in the art and the novel features of the invention will be defined in the appended claims.

in the accompanying drawings:

FIG. l is a diagrammatic view showing well head equipment, together with casing and tubing strings eX- tending downwardly into a well, and a valve assembly in the tubing embodying the present invention;

FlG. 2 is an enlarged detail view in vertical section, with certain of the parts shown in elevation, of a full open gate valve in accordance with the invention;

FIG. 3 is an enlarged detail view similar to FIG. 2, but showing the valve in a closed position;

FIG. 4 is a fragmentary view in transverse section, as taken on the line 4 4 of FIG. 2;

FIG. 5 is a fragmentary detail view in elevation, showing the valve gate mounting, this View being taken substantially on the line 5-5 of FIG. 4; and

FIG. 6 is a transverse sectional view as taken on the line 6--6 of FIG. 2.

Like reference characters in the several views of the adresse o; drawings and in the following detailed description designate corresponding parts.

Referring particularly to FIG. l, well apparatus is zshown, including ak casing l disposed in a well, with a tubing string 2 concentrically disposed in the casing. The tubing may be suspended in the casing at a point spaced substantially downwardly from the top of the casing by suitable means such as a tubing anchor (not shown). Above the anchor is a suitable packer. A hook-wall packer assembly 3 may be advantageously used thus eliminating the need for a separate anchor in some cases. The hook-wall packer 3 need not be described in detail in that it is a known type of packer. Generally, however, the packer assembly 3 includes a packer element d adapted to seal off the annulus between the casing and the tubing. Means such as a plurality of casing wall engaging slips 5 are employed for securing the packer in place. Operatively connected to the slips 5 is a plurality ofV friction pads 6 engageableY with the casing to set the slips S and prevent relative movement of the packer assembly 3 and the tubing 2 in one direction. Depending from the packer assembly is a suitable number of hooks 7 adapted for engagement with a similar number of lugs 3 carried by the tubing 2, whereby relative movement of the packer assembly 3 and the tubing 2 in the other di rection, is precluded.

-Interposed in the tubing string 2 between the hook- Wall packer assembly 3 and the upper end of the tubing is a novel fluid pressure operated valve assembly generally designated 9 which will be more speciiically described as the description progresses.

As previously noted, the valve assembly is adapted to be subjected to uid pressure. Such pressure is preferably derived from the production huid through well head equipment. This well head requipment includes a safety landing sub 10' carried by the upper end of the tubing string 2. Removably mounted on the upper end of the landing sub 10 as by a slip fit is an annular landing flange 11 which is interposed between upper and lower sections 12 and 13, respectively, of casing head means generally designated H. At its inner periphery, the landing ilange is provided with suitable seals or packing rings 11', so that the landing ange constitutes an upper barrier between the casing 1 and tubing 2 for preventing the direct flow of uid from the tubing into the casing. ln addition, the casing head section'13 is sealingly engaged at the upper extremity of the casingV 1 as by a threaded connection 1.

Disposed above the casing head l-l is a conventional Christmas tree T having tiow line F, F each having a ow valve V and V', respectively. The Christmas tree T also comprises a valve V between the casing head H and the flow lines F, F and a valve V disposed above the ow lines F, F. At the top of the Christmas tree is a cap C which may advantageously be itted with a gauge G or the like.

In accordance with the invention hereof, the huid pressure operated valve assembly 9 is adapted to be maintained open, that is, in a condition enabling the well to flow or produce through the tubing 2, responsive to fluid pressure in the annulus 14 between the casing ll and the tubing 2. Such Huid pressure may be derived from a number of sources.

For example, in FIG. l, duid communicationl is established between the ilow lines F, F and the annulus 14. ln this connection, a line 15 is tapped into the ow line F. This line 15 is joined with fa line 16 which is connected with the landing ange 11, the landing ilange havingT a passage 17 leading to the annulus i4. In addition the line 16 is extended as at 16 for connection to a pump or other source yot pressure fluid (not shown), and a vent line 18 is also connected to the line 16. Each of the lines 15, 16 and i3 is provided with a control valve and valves being respectively designated 19, 20 and 21.

At the other side of the Christmas tree T andV communicating with the flow line F is a pressure line 22 preferably having an orifice union 23 therein for limiting the rate of iiow of fluid from the ilow line F'. The line 22 is connected with a line 2d which establishes iiuid communication with the aunulus H through a passage 25 in lthe landing llange ll.

The line 24 has a manual valve 25 and a multiway valve 27 therein. The multiway valve 27 is adapted to selectively establish communication between the line 2d and a vent 2S and between the line 24 and an extension 24 of the latter, the llow from line 2d -to extension 24 being interrupted by the valve Z7 upon venting or" the line 24. Valve 27 may be o any desired constructiony but is preferably operable by a lever 27 for a purpose which will be hereinafter more fully described. y v

Also connected to ow line F is a pair of pilot valves 29 and 38, a manual valve preferably being interposed between each pilot valve 2,9 and 3d as at 3l and 32, respectively, and the line F'. A cross line 33 establishes communication between line 24 and the pilot valves 29 and 30, and each of said pilot valves is pro-vided with a vent 34 and 35, respectively. The details of the pilot valves are not germano and they may be of any desired construction, whereby one of the pilot valves, say pilot valve 29, is responsive to a drop in pressure in the line F' below `a predetermined valve to vent line 24 to the -atmosphere through vent 34, whereas the other pilot valve 3b is responsive to pressure in line F abo-ve a predetermined value to vent line 2d through vent 35.

As has been. previously stated, the valve assembly 9 is adapted to be maintained open 'responsive to iiuid pressure in the annulus 14. Accordingly, the valve assembly 9 includes a cylindrical housing .35 having `a suitable number of ports 37 leading from the annulus 14 into the housing.

Referring particularly to FIGS. 2 and 3, it will be seen that the housing 36 preferably includes a lower section 38 constituting a pressure cylinder and threadedly connected as at 39 with a coupling 4d adapted to be connected with the depending tubing string. An upper housing section 41 is threaded to the lower section 3.8 as lat 42, and at its upper end the housing 41 is threaded to a coupling 43 adapted to be connected to the tubing string above the valve 9. 'Suitable sealing means are employed for preventing the passage of iluid between the couplings 40 and 43 and the ends of the housing sections 38 and 41, respec tively, such as Oaring or other sealing elements 44 and 45. Another sealing element or O-ring 46 is interposed between the threaded ends of the housing sections at the connection 4E thereof.

At a point spaced below the lower extremity of the upper coupling 43, the upper housing section is provided with an annular shoulder 47 projecting radially inwardly. A valve seat d8 having a radial flange 49 is supported on the shoulder 47, with the flange 49 clamped between the :shoulder 47 and the lower extremity of the coupling 43. Preferably, an O-ring 5d or other sealing means is interposed between the inner periphery of the housing section dit and the flange i9 to prevent flow of well duid around the seat. The seat 48 has :a tapered or beveled face adapted to be engaged by an annular complementary tapered or beveled gate valve 51.

Gate valve 51 comprises a disc-like base 52 on which is secured an annular tapered valve washer 53 which may be composed of Te-lion, rubber, or other suitable material. The washer 53 is secured in place by a circular disc 54 having la marginal flange S5 overlying the washer 53, this disc 54 having a threaded stem 56 which projects through a central opening in the base 52 into threaded engagement with a cross member 57. At its opposite ends, the cross member 57 is bifurcated as at 58 and 59, and the cross member is pivotally supported on an ear di! depending from one side of the valve' seat 43 and disposed in the bifurcated end 53- of the cross member 57, a pivot pin 61 extending through the interengaged ear and bifurcations.

At its other end, the cross member 57 is pivotally connected by a pin 62 with an end of a longitudinally extended link 63, said link being connected at its other end to fluid pressure operated means for shifting the link in opposite directions so as to close and open the valve.

Such fluid pressure operated means comprises a sleeve 64 reciprocably disposed in the lower housing section 38 and projecting upwardly into the upper housing section 4l. It will be observed that housing section 3S projects radially inwardly to provide a shoulder e5 and an annular space 66 is defined between the sleeve 64 and the housing section 38, into which space fluid may flow from the annulus 14 through the ports 57. At its lower end the sleeve 64 is formed with a radially projecting flange 67 constituting a piston. Sealing means such as an O-ring 68 and an O-ring 69 are respectively interposed between the upper end of sleeve 64 and the'inner periphery of the housing section 38 and between the piston 67 and said housing section 3S, so that fluid admitted to the space 66 can not escape therefrom. A coiled compression spring 79 is interposed between the shoulder 65 and the piston 67 so as to normally bias the sleeve 64 to the position shown in FIG. 2. At its lower extremity the sleeve o4 is provided with a beveiled surface 64' which is responsive to the pressure of production fluid to effect upward movement of sleeve 64.

j Means are provided for interconnecting the link 63 previously referred to with the sleeve 64. Such means preferably comprises a collar 71 disposed about the sleeve 6d and hxed thereon as by pins or keys 72. As is best seen in FIG. 6, in order to facilitate assembly, the collar 71 is bored eccentrically and provides an enlarged link supporting portion at one side thereof having upstanding ears '73, between which the lower end or" the valve operating link 63 is connected as by means of a pivot pin 74. The upper end of the sleeve 64Vis axially slotted or recessed as at 7S, so that upon upward movement of the sleeve o4 the link e3 is free to span the sleeve through the slot '75 and assume the position shown in FIG. 3, thus closing the valve.

As is best seen in FIGS. 2 and 3, the inner diameter of the upper valve housing section 4l is substantially greater than the minimum inside diameter of the couplings 4G and 43. Accordingly, when the valve El is full open as shown in FlGS. 2 and 4, it is effectively recessed in the housing section 4l and maximum fluid How through the valve assembly is permitted, limited only by the inside diameter of the coupling 4t? and 43.

A further advantage in this structure is the fact that wire line tools (not shown) of any desired type may be run into the well. The valve assembly 5 offers no obstruction to the passage of such wire line tools as may be employed in perforating, fracturing, cementing, testing or other operations. Instead, as an extremely advantageous feature of the present construction, the annulus 14 may be pressurized to open the valve, as will hereinafter more fully appear, during such wire line operations.

As has been previously described, the multi-way valve 27 in line 24 has a lever 27' for effecting operation of the valve. Since, an important feature of the present invention is the fact that the valve Si may be automatically shut oi if the well head equipment should be subjected to damage, such as for instance from tide or wind driven objects, in the case of an offshore well, the lever 27 has an end of a safety cable dit connected to its free end (see FlG. l). Accordingly, the valve 27 may be operated by pulling the cable dit responsive to certain emergency conditions.

The structure heretofore described. will automatically shut off ow from the well, or if desired such flow may be interrupted manually, and a number of safety shut offs are provided.

in this connection, assuming that the well is in condition for production but requires swabbing, the valves l@ and 2 in line l5 may be opened, while sweet oil or the like is pumped into the annulus 14 through lines lr6 and 16, so as to lill the annulus i4 and the annular space 66 in the valve assembly 9. When these spaces are filled with sweet oil or the like, such oil will commence to flow through valve 26 which may then be closed. Continued operation of the sweet oil pumping means (not shown) will build up pressure in the annulus so as to cause the transmission of such fluid pressure through the ports 37 in the lower valve housing section 38, into the annular space 66 behind the piston 67 on sleeve 64. Such fluid pressure will assist the spring 70 in maintaining the valve open as shown in FIG. 2. Under such circumstances the valve assembly is full open anda swab (not shown) may be run down on a line to the producing zone. The well may then be swabbed into production flow as is customary.

When `the well is flowing, the valve V'" will be closed off, while production fluid passes through either or both v of flow lines Fand F' through ow valve V and V. Assuming that dow is passing through both of lines F and F', valve 20 in line 16 will be closed off, as will be vent valve 21 and vent 28 through multiovay valve 27, but valves 19, 26, 31 and 32 will be open. Accordingly, pressure from theproduction fluid will be imposed on the sweet oil in the annulus 14 and in the annular space 66 in the valve assembly 9.

As long as the well is producing normally under predetermined pressure, vents 54 and 35 of' under and over pressure pilot valves 29 and 3() will remain closed. However, should production pressure exceed or fall below the pressure which the pilot valves are set for, flow between line 24 and flow line F will automatically be vented to the atmosphere. This will relieve fluid pressure in the annulus 14 and annular valve space 66; whereupon the further flow of production Huid will act upon lower end surface 64' of sleeve 64, thus shifting the sleeve 64 to the position of FlG. 3 to close the valve gate 51 on the seat 4S. It will be noted in FIG. 3, that the sleeve 64 extends upwardly into engagement with the gate 51 when the later is closed so as to aid in preventing leakage past the valve. Except for the slot 75, the sleeve 64 has annular bearing contact with the gate 5l, with the result that seating of the valve is positively effected over the entire annular valve seat face 58.

Accordingly, the well is automatically shut in upon excessive or diminished ow pressures. The same result may be accomplished by opening vent valve 2l, which will relieve the fluid in the annulus 14 from production pressure. Thus, manual ow control is effected.

Of course, in the event that the casing head H, which has a slip lit with the casing and tubing should be inadvertently separated from the casing as by reason of a collision of some objectV with the platform or with the well head equipment, or in the absence of an over pressure pilot valve such as that indicated at 30, should be blown olf, the pressure in the annulus will also be reduced. Thereupon, the valve 9 will function as a subsurface blowout preventer.

lt will now be apparent, that, in accordance with the objectives stated at the commencement hereof, the invention provides means for shutting off well flow, which comprises, broadly, a uid pressure responsive valve disposed in a tubing string and adapted to be closed by production fluid pressure, said valve communicating` with the annulus between the tubing and well casing above a packer; whereby upon pressurizing the annulus above the packer the valve will be opened, and upon depressurizing the annulus responsive to one or more of a number of different occurrences at the well head, the valve will be closed and prevent further flow. These occurrences at the well head, as has been previously mentioned, may be purely manual, as in the: case of opening vent valve 21, or on the other hand, such occurrences may be automatic such as blowing off of the well head, opening of over or under pressure vents, opening of a vent responsive to collision or the like.

antenas Other means for d'epressurizing the annulus le, and other situations under which closure oi the valve may be desirable will be apparent to those skilled in the art, but changes and alterations may be resorted to without departing from the spirit of the invention as defined in thev appended claims.

We claim: p

l. A flow control valve for wells, comprising: a housing adapted to be installed in a tubing string in a well; said housing having a flow passage therethrough; a valve seat in said housing circumscribing said passage; a gate valve pivotally mounted at one side or" said seat and movable towards and away from said seat; operating means in said housing for moving said gate valve as aforesaid, said operating means including a iiuid pressure operated actuator; means interconnecting said' actuator with said gate valve; said actuator including a sleeve coaxially disposed in and radially spaced from said housing; means on said sleeve forming4 a piston slidably engaged with said housing; said sleeve and said housing being sealingly engaged in axially spaced relation to said piston and a fluid pressure inlet for admitting fluid into the space between said sleeve and' said housing.

2. A ow control valve for wells, comprising: a housing adapted to be installed in a tubing string in a well; said housing having a ilow passage therethrough; a valve seat in said housing circumscribing said passage; a gate valve pivotally mounted at one side of said seat* and movable towards and away *from said seat; operating means in said housing for moving said gate valve as aforesaid; said operating means including a fluid pressure operated actuator; means interconnecting said actuator with said gate valve; said actuator including a sleeve coaxially disposedin and radially spaced from said housing; means on said sleeve formingl a piston slidably engaged with said housing; said sleeve being slidably engaged with said' housing in axially spaced relation to said piston and forming a space therebetween; a uid pressure inlet for admitting fluid into the space between said sleeve and said housing; and a spring disposed in the space between said sleeve and piston and normally urging said sleeve in one direction.

3. A ilow control valve for wells, comprising: a housing adapted to be installed in a tubing string in a well; said housing having a flow passage therethrough; a valve seat in said housing circumscribing said passage; a gate valve pivotally mounted at one side of said seat and movable towards and away from said seat; and operating means including a sleeve shiftably disposed in said housing for moving said gate valve as aforesaid; and a link pivotally connected to said sleeve and to said gate valve; said sleeve extending axially beyond the connection ot the sleeve tothe link towards said gate valve and engaging said gate valve when the latter is closed.

4. A iow control valve for wells, comprising: a housing adapted to be installed in a tubing string in a well; said housing having a flow passage therethrough; a valve seat in said housing circumscribing said passage; a gate valve pivotally mounted at, one side of said seat and movable towards and away from said seat; operating means including a sleeve shiftably disposed in said housing for moving said gate valve as aforesaid; and a link pivotally connected to said sleeve and to said gate valve;

said sleeve extending axially beyond the connection ofl Y able towards and away from said seat; operating means on said housing for moving said gate valve as aforesaid;

said operating means including a fluid pressure operated actuator; and means interconnecting said actuator with said gate valve; said actuator including a sleeve coaxiall and shiftably disposed in said housing at the opposite side of said gate valve from said seat; means dening a chamber between said sleeve and housing including a iiange on said sleeve; said flange constituting a piston; said housing having an inlet for admitting pressure fluid to said chamberfor shifting said sleeve in a direction to open said gate valve; said sleeve having an extension projecting toward said seat from said interconnection ci: said interconnecting means to said sleeve for engagement with said gate valve when the latter is seated.

6. A. liow control valve for wells, comprising: a housing adapted to be installed in a tubing string in a well; said housing having a ow passage therethrough; a valve seat in said housing circumscribing said passage; aV gate valve pivotally mounted at one side of said seat and movable towards and away from said seat; and operating means on said housing for moving said gate valve as aforesaid; said operating means including a fluid pressure operated actuator; and means interconnecting said actuator with said gate valve; said actuator including a sleeve c oaxially and shiftably disposed in said housing; means defining a chamber between said sleeve and housing including a iiange on said sleeve; said' sleeve being sealingly engaged with said housing in axially spaced relation to said ange and forming a space therebetween; said ange constituting a piston; said housing having an inlet for admitting pressure i'luid to said charnber; for shifting said sleeve in one direction; said sleeve having an end area subjected to the iiow of fluid through said passage for shifting the sleeve in the other direction.

7. A iiow control valve including: a housing; said housing having a flow passage therethrough; a valve seat in said housing circumscribing said passage; a gate valve pivotally mounted at one side of said seat and movable towards and away from said seat; and operating means in said housing for moving said gate valve as aforesaid; said operating means including a iiuid pressure operated actuator; and means interconnecting said actuator with said gate valve; said actuator having an extension projecting toward said seat from the connection of said interconnecting means to said actuator for engagement with said gate valve when the valve is closed.

8. A iiow control valve, including: a housing; said housing having a ow passage therethrough; a valve seat in said housing circumscribing said passage; a gate valve pivotally mounted at one side of said seat and movable towards and away from said seat; and operating means in said housing for moving said gate valve as aforesaid; said operating means including Aa tluid pressure operated actuator; a link interconnecting said actuator and said gate valve; and means for normally opening said valve; said actuator having an extension projecting towards said seat from the connection of said link to said actuator for engagement with said gate when the valve is closed.

9. A iiow control valve, including: .a housing; said housing having a iiow passage therethrough; a valve seat in said housing circumscribing said passage; a gate valve pivotally mounted at one side of said seat and movable towards and away from said seat; operating means in said housing for moving said gate valve as aforesaid; said operating means including a iiuid pressure operated actuator; a link interconnecting said actuator and said gate valve; said link extending across said flow passage when said gate is closed; said actuator having an extension projecting towards Said seat from the connection of said link to said actuator for engagement with said gate valve when the valve is closed; and said extension being provided with a recess for the reception of said link when said extensionV is engaged with said gate valve.

extending into a well; said housing having a liow pass-age therethrough; a valve seat at one end of said housing circumscn'bing said flow passage; a gate valve shiftably mounted adjacent to said seat for pivotal movement into engagement with said seat and to a position closely adjacent to said housing; means for shifting said gate valve including a sleeve shiftably disposed in said housing; a link connected at one end to said sleeve and at the other end to said gate valve; said sleeve having an end portion projecting toward said gate valve from the pivotal connection of said link to said gate valve for engagement with said gate valve when said gate valve is disposed on said seat.

11. Well ow control equipment for shutting off the ow of iiuid from a Well having a casing therein, comprising: a casing head; a ow line leading from said casing head; production tubing extending into said well from said casing head; packer means forming a seal between said tubing and said casing; a iluid pressure operated valve assembly in said tubing above the packer means; means for conducting production uid under pressure from said casing head to the space :between said casing and said tubing above said packer means; said valve assembly including a housing having an opening communicating with said space between said casing and said tubing above said packer means; a sleeve shiftably disposed in said housing and having an annular pisten at one end thereof slidably and se'alingly engaged With said housing to form a chamber; said opening in said housing being located at one side of said annular piston and leading into said chamber for admitting uid pressurefrom the space between said casing and said tubing into said chamber, and the other side of said annular piston 'being subjected to Well fluid pressure in said tubing; a valve seat in said housing; and valve means at one end of said sleeve engageable with said scatto prevent the ow of fluid through said housing when said annular piston surface is subjected to Well production pressure overcoming the effect of fluid pressure in said space above said packer upon said annular piston.

References Cited in the tile of this patent UNITED STATES PATENTS Natho Feb. 5, 1957 2,785,755 En Dean Mar. 19, 1957 2,786,535 Boer et al Mar. 26, 1957 2,812,821 Nelson Nov. l2, 1957 2,921,601 Fisher Jan. 19, 1960 

